POS1092 THE IMPACT OF A STRUCTURED WEIGHT LOSS PROGRAM ON PHYSICAL FITNESS IN PATIENTS WITH PSORIATIC ARTHRITIS AND OBESITY COMPARED TO MATCHED CONTROLS: A PROSPECTIVE INTERVENTIONAL STUDY
Authors: A. Bilberg, I. Larsson, S. Björkman, E. Klittmar, B. Eliasson, E. Klingberg
Journal: Annals of the Rheumatic Diseases (2022)

Background Obesity is over-represented in patients with psoriatic arthritis (PsA) and associated with increased disease activity. We have previously shown that weight loss treatment with Very Low Energy Diet (VLED) in patients with PsA and obesity was associated with a sustained weight reduction and significant improvement of the disease activity in joints, entheses and skin during 24 months follow-up. A side effect with a large weight loss is however a concomitant reduction of muscle mass, which can negatively affect physical fitness. Objectives This study aimed to evaluate the effects of weight loss treatment on physical fitness i.e., muscle strength, cardiorespiratory fitness, body composition and self-reported physical functioning, in patients with PsA and obesity compared to matched controls undergoing the same treatment. Methods In total, 46 patients with PsA (Caspar criteria) and obesity and 52 controls (matched for age, sex, body weight and height) were included. VLED (640 kcal/day) was provided to all participants for 12-16 weeks depending on baseline BMI (&lt;40 or ≥40 kg/m 2 ), followed by reintroduction of energy restricted diet. Brief support for physical activity was given. Primary outcome was muscle strength, assessed in hand-grip with a dynamometer (Grippit) and in leg muscle by measuring the time (seconds) needed to stand up ten times from a standard chair (Timed Stand Test: TST). Secondary outcomes were cardiorespiratory fitness (O 2 l/ min), measured with the Åstrand’s submaximal bicycle test, body composition analyzed with dual energy x-ray absorptiometry and physical functioning, assessed with the Short Form 36 Health Survey Physical Component Score (SF-36PCS). Outcomes were evaluated at baseline (BL), six (M6) and 12 months (M12). Results In total, 41 PsA patients (median age 54; 63% women) and 42 controls (median age 54; 74% women) completed the treatment. At M6 the median weight loss since baseline in patients and controls was 18.9 kg and 23.0 kg respectively (p=0.546), and at M12 16.1 kg and 16.6 kg (p=0.885). Significant changes (all p&lt;0.001) were seen at M12 in the body composition of both patients and controls, with decreases in total fat mass (-30.1% vs. -27.4%), total lean mass (-7.0 % vs -8.3 %), lean arm mass (-13.7% vs -2.4%) and lean leg mass (-6.0% vs -8.6%). Leg muscle strength did however improve in both patients and controls at M6 (p&lt;0.001) and remained improved at M12 (p=0.001 and p&lt;0.001), while hand-grip strength was unchanged in both groups. Cardiorespiratory fitness increased in controls at M6 (p=0.018) and M12 (p=0.028), but not in the patients. Physical functioning improved in both groups at M6 and remained improved at M12. Conclusion Patients with PsA and obesity can benefit from weight loss treatment without risk of deterioration in muscle strength. However, muscle strength and cardiorespiratory fitness were below suggested normative values for the majority of the patients at all timepoints, implying that more structured exercise strategies might be warranted to counteract physical fitness deficiencies in patients with PsA undergoing weight loss treatment. Table 1. PsA patients n=41 Controls n=42 BL M12 p-value BL M12 p-value BMI, kg/m 2 35.2 34.1–38.1 30.5 28.0–32.9 &lt;0.001 38.5 36.9–41.7 32.6 30.3–34.8 &lt;0.001 Hand-grip strength, N 268 196–326 244 180–352 0.457 304 280–348 300 244–384 0.573 Leg strength TST, sec 26.9 22.1–35.4 23.2 19.4–30.4 0.001 23.7 21.0–32.8 20.1 16.8–25.9 &lt;0.001 Cardiorespiratory fitness, O 2 l/ min 2.0 1.8–2.2 2.1 1.8–2.6 0.098 2.0 1.6–2.3 2.1 1.7–2.4 0.028 Tot fat mass, kg 48.5 41.7–56.7 33.9 25.9–40.5 &lt;0.001 50.7 46.2–59.2 36.8 27.8–39.5 &lt;0.001 Tot lean mass, kg 51.9 45.9–61.8 48.3 43.6–58.3 &lt;0.001 49.7 46.9–58.6 45.6 44.5–57.9 &lt;0.001 Lean mass arm, kg 2.79 2.48–3.85 2.43 2.10–3.45 &lt;0.001 2.63 2.39–3.34 2.57 2.22–3.36 &lt;0.001 Lean mass leg, kg 8.9 8.0–10.9 8.4 7.2–9.8 &lt;0.001 9.1 8.5–10.4 8.1 7.7–9.8 &lt;0.001 SF-36 PCS,score 0-100 35.8 24.9–46.3 46.1 34.5–49.8 0.008 45.7 32.9–50.9 51.6 43.8–55.4 &lt;0.001 Figures are Median IQR Disclosure of Interests None declared